The present invention relates to machine tools, and particularly to lathes.
A lathe is known in which three longitudinally extending, laterally spaced guides are mounted on a frame to extend substantially parallel to one another. Two carriages are slidably mounted on the guides for movement therealong, the two carriages being movable in parallel directions. Each of the carriages is mounted on a respective one of the outer guides and on the central guide.
In this known lathe, the central guide and the two outer guides are formed by broad hardened steel bars mounted on an under-frame which is a casting. Each of the two carriages is supported on one of the outer guides, and both carriages are supported conjointly on the central guide.
Each carriage is guided laterally by the engagement of a lower carriage segment between the respective outer guide and the central guide, this carriage segment resting without play, on the facing longitudinal sides of the said guides, which sides are spaced from one another. As a result, it is not possible to shift the carriage on the guides transversely to the carriage adjustment direction and transversely to the guide members.
Each carriage is guided vertically by way of counterstrips, located on the underside of the carriage, which rest on lower support faces on the corresponding guides. This prevents the carriages lifting off the guides.
Accordingly, both the guides which guide each carriage are involved in the lateral guiding and in the vertical guiding of the carriage, that is all three guides are involved in the guiding of both carriages. This makes it necessary that the three guides are all precisely parallel to one another in order to ensure that the carriages can move parallel to one another. This can only be achieved at considerable manufacturing expense.
It is an object of the present invention to provide a machine tool, such as a lathe, having the features described at the outset, in which for lateral guiding of the carriages precise parallel alignment of the guides relative to one another is no longer necessary.